Several things that are legal, routine, or barely noticed back home can get you arrested in Japan. The list of things that are illegal in Japan for tourists is longer than most visitors expect, and it includes common cold and ADHD medications, pocket knives carried without a specific reason, cycling after a single beer, photographing strangers, cannabis in every form, and overstaying your visa by even a day. The penalties are real, and the police can hold you for up to 23 days before deciding whether to file a charge.
Medications You Cannot Bring Into Japan
This is where tourists get caught most often, usually at the airport. Several drugs that are sold over the counter or on routine prescription in the United States, Canada, and Europe are controlled or banned in Japan. Adderall and other amphetamine-based ADHD medications are prohibited outright. Pseudoephedrine, the active ingredient in Sudafed, Actifed, and Vicks inhalers, is a controlled stimulant raw material. A valid prescription from your home country does not protect you. If the substance is illegal in Japan, you can be arrested at customs.1U.S. Embassy & Consulates in Japan. Bringing Over-the-Counter Medicine and Prescriptions into Japan
For allowed medications, the Ministry of Health, Labour and Welfare permits travelers to bring up to a one-month supply of prescription drugs and a two-month supply of non-prescription drugs without any paperwork. Anything over those amounts, or any controlled substance, requires an import certificate called a Yunyu Kakunin-sho, obtained before you travel.2Ministry of Health, Labour and Welfare. Information for Those Who Are Bringing Medicines for Personal Use Psychotropic medications such as methylphenidate (Concerta, Ritalin) cannot be mailed into Japan at all; they must be carried in person with proper authorization.3Narcotics Control Department. Application Guidance
Check every medication in your bag against Japan’s rules before you fly. “I didn’t know” is not a defense.
Drugs, Including Cannabis
Japan’s drug laws are among the strictest in the developed world, and the penalties are heavy regardless of quantity. Heroin, cocaine, MDMA, methamphetamine, opium, and cannabis are all prohibited. Methamphetamine possession or use carries up to 10 years in prison under the Stimulants Control Act, with fines up to 10 million yen (roughly $64,000) for sale or distribution.4Ministry of Health, Labour and Welfare. About the Penalties for Drug Offenses in Japan
Cannabis changed significantly in December 2024, when revised legislation reclassified it as a narcotic under the Narcotics and Psychotropic Substances Control Law. Previously, only possession was criminal. Now recreational use alone can bring up to seven years in prison.5Global Forum. Cannabis-Derived Drugs in Japan: New Legislation and Outlook MDMA and cocaine carry similar seven-year maximums. If you use cannabis legally in your home country, do not assume residue, vape cartridges, or edibles are safe to bring. CBD products are legal in Japan only if they contain no THC, and the rules on cannabinoids are tightening every year.
Knives and Weapons
Japan has some of the tightest civilian weapons restrictions in the world. Handguns, rifles, machine guns, and their ammunition and parts are banned under the Firearms and Swords Control Law, and importing them is separately banned under the Customs Tariff Law.6Ministry of Foreign Affairs of Japan. National Report on the Implementation of Programme of Action to Prevent, Combat and Eradicate the Illicit Trade in Small Arms and Light Weapons in All Its Aspects Few tourists arrive with firearms. Many arrive with knives.
Daggers and double-edged knives with blades over 5.5 centimeters (about 2.2 inches) are prohibited, as are swords and spears with blades over 15 centimeters.7Misawa Air Base. Revised Japanese Law Cuts Down on Knives Separately, carrying any bladed object, including a small folding knife, without a legally accepted reason is an offense. “For personal protection” is not a valid reason. “It’s handy to have” is not a valid reason. Fishing, camping, and cooking are accepted purposes, but you must be able to explain exactly why the knife is on you at that moment.
If you buy kitchen knives as souvenirs, leave them sealed in their retail packaging until you leave the country.
Drinking Before Driving or Cycling
Japan’s drunk driving threshold is far lower than most Western visitors expect. You can be charged at a blood alcohol level of 0.03 percent, roughly a third of the legal limit in most U.S. states. At 0.08 percent or above, the offense escalates to driving while intoxicated, carrying up to five years in prison or a fine of up to 1 million yen (about $6,400).
Passengers are also criminally liable. Riding in a car with a drunk driver is a separate offense punishable by up to three years in prison or a fine of up to 500,000 yen. The same applies if you provide alcohol to someone you know will drive, or lend your car to someone intoxicated. A drunk driver who causes a fatal accident faces up to 20 years.
Bicycles count as vehicles under Japan’s Road Traffic Act, so all of these rules apply to cycling. Renting a bicycle in Kyoto and riding back to your hotel after dinner and a beer is a crime.
Photographing People
Japan passed a national photo voyeurism law in 2023. It explicitly prohibits photographing someone’s body or sexual acts without consent, including filming children in a sexual manner. Violations carry up to three years in prison or a fine of up to 3 million yen (roughly $19,200). Distributing or possessing such images is also criminal.
General street photography is not illegal, but photographing identifiable individuals without consent can draw complaints and police involvement under various prefectural ordinances, especially when a subject feels their privacy was invaded. Ask before pointing a camera at someone, and avoid photographing children you do not know.
Gambling
Private-sector gambling is a criminal offense under Article 185 of Japan’s Penal Code, punishable by a fine of up to 500,000 yen. Habitual gambling raises the penalty to up to three years in prison, and running a gambling operation carries three months to five years.8Japanese Law Translation. Penal Code The only legal forms of wagering are government-run bets on horse, bicycle, motorcycle, and motorboat races, plus the national sports lottery.9Chambers and Partners. Gaming Law – Japan Online betting is permitted only for those authorized sports.
Pachinko parlors operate in a long-standing legal gray zone. Players receive tokens rather than cash and exchange them off-site; the system has run for decades without being shut down. For a visitor, the practical rule is simple: do not place a cash bet on anything other than the authorized races and the national lottery.
Downloading and Uploading Copyrighted Material
Japan enforces copyright law aggressively. Downloading copyrighted music, movies, manga, or other protected works without authorization is a criminal offense carrying up to two years in prison or a fine of up to 2 million yen. Uploading is treated far more severely, with up to 10 years in prison and a fine of up to 10 million yen.
A 2020 amendment also criminalized the use of “index sites” or apps that provide links to pirated content, with penalties up to three years in prison. Prosecution requires a formal complaint from the copyright holder.10Agency for Cultural Affairs. Amendment to the Copyright Act Approved by the Ordinary Session If you stream or torrent on hotel Wi-Fi the way you might at home, understand that the exposure is real.
Minor Public Conduct
Littering is illegal under local ordinances across Japan, and some municipalities impose on-the-spot fines. Public intoxication that spills into disorderly behavior can lead to detention. Excessive noise, especially in residential areas at night, can draw complaints under nuisance provisions.
None of these carry heavy sentences on their own. They matter because they bring police contact, and police contact escalates quickly in Japan into document checks and formal processes. A noise complaint can end with a search of your bag.
Overstaying Your Visa or Working on a Tourist Visa
Overstaying a visa, even by one day, is a criminal offense punishable by up to three years in prison or a fine. In practice, most overstayers are detained and deported rather than prosecuted, but a standard deportation triggers a five-year re-entry ban.
Working without proper authorization is a separate offense. This includes any paid work on a tourist visa, work beyond the hours permitted by a student visa, or work outside the scope of your designated activity. Lying on a visa application, residence card, or landing form adds another criminal charge.
If you realize you have overstayed, turning yourself in through Japan’s departure order system typically allows you to leave without detention and reduces the re-entry ban to one year, provided you have not been previously deported or committed other offenses during your stay.
What Happens If You Are Arrested
Japan’s criminal procedure differs sharply from what most Westerners expect, and the first hours matter most. Police can hold you for up to 72 hours before requesting a detention extension from a judge. If granted, and extensions are granted in the vast majority of cases, you can be held for two further 10-day periods, bringing total pre-charge detention to 23 days. Prosecutors are not required to file charges during this time.
Interrogations happen without a lawyer in the room. Japan does not recognize a right to counsel during questioning; your attorney can visit you in a holding cell but cannot sit beside you while police question you. Japan’s conviction rate exceeds 99 percent, and confessions obtained during this detention window play a large role in that figure.
Ask for the Duty Attorney Immediately
If you are arrested, you can request a duty attorney, called a toban bengoshi, at no cost for the initial visit. Say to the police: “Please call the duty attorney.” The station will contact the local bar association, and a lawyer will come to meet you in the holding cell with no officers present. The attorney explains your rights, walks you through the procedure, and contacts your family or embassy.11Japan Federation of Bar Associations. If You Are Arrested! – About Duty Attorney System You do not need to know any lawyer in Japan ahead of time. The system is built for people who do not.
The 23-day clock runs whether you have a lawyer or not. Asking for the duty attorney at the first opportunity is the single most useful step you can take.